Valve-gear for compound engines



(No Model.) 3 Sheets-Sheet 1. J. O. H. STUT.

VALVE GEAR FOR COMPOUND ENGINES.

-Patented June 4. 1889.

n Wnhinginm n. a

3 SheetsShet 2.

(NoModeL) J. O. H. STUT. VALVE GEAR FOR GOMPOUND ENGINES.

Patented June 4, 1889.

N PETERS. Phalo-Ulhagmphur. w-shin mn. B. C.

am t 8 .6 h S m. e 6 h s 3 m U T S H nu J (-No Model.)

VALVE GEAR FOR COMPOUND ENGINES.

Patented Jun 4. 1889,

*Qde/ N. PETERS, Photo-Lithograph. Washingion, D C.

U ITED STATES PATENT OFFICE. 7

JOHN CH. HENRY STUT, OF SAN FRANCISCO, CALIFORNIA.

VALVE-GEAR FOR COMPOUND ENGINES.

SPECIFICATION forming part of Letters Patent No. 404,509, dated June 4, 1889.

Application filed December 28,1888. Serial No. 294,865. (No model.)

To all whom it may concern.-

Be it known that 1, JOHN CH. HENRY STUT, of the city and county of San Francisco, State of California, have invented an Improvement in Valve-Gear for Compound Engines; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to improvements in cut-off mechanism for compound engines havin g cranks'at right angles and an intermediate receiver or reservoir, into which the steam is exhausted from the primary or high-pressure cylinder, and from which it is admitted to the low-pressure cylinder by suitable valve-gear.

The object of my invention is to provide a means by which the cut-off mechanism of the expansion-cylinder is regulated by a governor or governors of the initial and expansion cylinders, which are coupled together in such a manner that they act in unison.

It also consists in an adjustable mechanism whereby the cut-off of the expansion-cylinder may be changed with relation to that of the initial cylinder.

Referring to the accompanying'drawings for a more complete explanation of my invention, Figure 1 is an end elevation showing the initial and expansion cylinders, the intermediate receiver, and the connecting-pipes and valve-gear, and also the connecting device between the two. Fig. 2 is.an enlarged view of the cut-off mechanism of the expansion-cylinder, and also a partial section of the dashpot. Fig. 3 is a plan view of the link and dash-pot and a horizontal section of the governor-spindle. Fig. 4 is a vertical section of the disk or link taken through the plane of the axis. Fig. 5 is a front view of the same.

Host of the modern compound receiver engineshave a variable automatic cut-off onthe initial cylinder, but the cut-off for the steam of the expansion-cylinder is set by hand at a fixed point, and. this point is determined when the engine is running, so as to give the best general results. After being set there is no variation from it, whether the engine is working with high or low pressure steam or a light or heavy load. In some cases a governor for the initial cylinder and a governor forthe expansion-cylinder have been employed,-working independent of each other; but the results obtained from this constructionarenot found so satisfactory as those from the variable cut-off for the initial cylinder and fixed cut-off for the expansion-cylilr der. The great disadvantage of this kind of cut-offs is that a drop in the pressure of the steam from the initial cylinder to the receiver very often occurs, and at other times a comthe steam will be cut off in the expansion-cylinder earlier or later with reference to the cut-off in the initial cylinder, and thus retain the pressure in the receiver, so that there will be no drop in the exhaust from the initial cylinder into the receiver, and consequently no loss of power.

In the present case I have shown my invention as applied to what is known as the ONeill cut-off, patented in January and May, 1883; but I do not confine myself to any particular cut-off mechanism, as my invention is applicable to any automatic cutoff, with only such changes in form of construction as will adapt it mechanically to the particular style of cut-off employed. In the drawings, Ais the initial cylinder, and B is the expansion-cylinder, having the usual piston and connecting-rods, by which the power is transmitted to a common crankshaft, the cranks being set upon this shaft at right angles to each other, so that the steam which is exhausted from the initial cylinder, will be admitted to the receiver, and from this to the expansion-cylinder when the initial piston has completed one-half of the following stroke.

0 is the receiver into which the steam exhausted from the initial. cylinder passes through an exhaust-pipe D, and E is a pipe leading from the receiver to the valvc-cham ber of the expansion-cylinder, so that steam taken from the receiver will be delivered'into the expansion-cylinder at the proper times by the valve mechanism.

F is the governor of the initial cylinder, and I which is fulcrumed with relation to each of the governors, as shown, and the vertically-m ov- By the i gear and cut-off mechanism of each engine, j

and by the inner ends I mean those ends which connect with the cut-off mechanism.

The outer ends of these two levers have connecting-rods J J, with ball-joints at the upper ends, which unite them with cranks K upon a shaft L, this shaft being journaled with suitable relation to the governor mechanism and the horizontal levers II and I. It

will-beseen by reason of this connection that i v i i off mechanism, so that the cut-off will take whateyer movement takes place in the governor of the initial cylinder" will be transmitted to the governor of the expansioncy-li11der,

and that the two will operate together and si- 1 multaneously at all times.

In case only onef governor should be used for both engines the proportions of the levers to the cut-off mechanism will be the same as above.

The governor of the initial cylinder, operating upon the lever II acts directly upon thecut-otf: mechanism of this cylinder, with which it is connected :by a rod, M, which unites the inner end of the lever II with the rocker-arm N of the cutofi mechanism.

The connection of the inner end of the rod I with the cutoff mechanism of the expansion-cylinder is made in a different manner, as i now proceed to describe. The lever I is supported upon the fulcrum or standard ,0,

which in the present case I have shown as loosely jointed to a supporting-lug at P. The

lever I is connected with thevertieally-moving portion of the governor at the point Q 5 and it will be seen that as the go vernor-weight 1 rises or falls with the varying speed of the governor it will raise and depress the out-er' end of the lever, as shown in the dotted lines, while the inner end will be correspondingly f depressed or raised.

As the governor-weight j must rise and fall in a straight line, the fulcrum-standard is allowed to move slightly 5 about its jointed support at I to acc omm,odate itself to the vertical movement of the Stem.

The inner end of the lever I is connected by a rod R with a crank-arm S, which is fixed 5 upon one end of the horizontal shaft S, jouri naled in the sleeve T, as shown plainly in Fig. 3.

Upon the opposite end of this shaft is fixed a slotted link U, which in the presentf Vithin this i to receive the lower end of the radius-rod W", I

the upper end of which is connected with the rocker-arm Y, which is fixed to the shaft Z.

This shaft carries the rocker-arms which actuate the tripping mechanism oi. the cut-elf and thus fix the point at which steam is cut ofif in the cylinder. The curve of the link or its slot forms a segment of a circle corresponding with the length of the radius-rod W. A thumbscrew a is made on the end of the pin V, and by means of this screw the pin and the sliding block V may be clamped at any point desired in the slot of the link.

\Vhen fixed in the center, it will be manifest that the action of the oscillating link will not aitect the radius-rod V and the rocker- ,arm cut-01f mechanism in anyway; but when moved either to the right or left of the center the movements of the crank S, which is actuated from the lever I by the governor, as above described, will change the position of the rockenarm Y, either raising or lowering it, and thus moving the trip-cam of the cutnections of the governors of the two cylinr ,ders, previously described, any action of the governor of the initial cylinder which varies'the point at which steam is cutoff from that cylinder will be immediately communieated to the governor of the expansion-cylinder, and thlbllgh the radius-rod NY the cut-oil 5 of that cylinder will be adjusted to ,corre spend with the action whichhas taken place in the initial cylinder. It will be maiiifest that this adjustment maybe made so that the cut-oil of the expansion-cylinder will correspond with that of the initial cylinder when the radiusrod set to one side of thecenter of oscillation of the link U, or it will be pro portionately against the cutcit of the initial cylinder when the radius-rod is set to the opposite side of thecenterof oscillation of the link. The approximate cut-oflf of the initial cylinder is shown by an indicator m, with a 1 corresponding scale over which it moves.

The operation may be illustrated as fo-llows: Let it be assumed that the initial cylinder cuts on? the steam at one-fourth of thestroke, and the exhaust-steam from the same passes into the receiver having a pressure of, say, thirty-five pounds. Let it .be assumed that the pressure in the receiver also thirty-five pounds at this instant, so that there will be no drop in the exhaust-steam pressure from the initial cylinder. Let the cut-off of the expansion-cylinder be set and fixed so that it will take from the reservoir the same volume of steam that the initial cylinder disclmrgin g into the receiver, thus maintaining a constantpressure of thirty-five pounds in the receiver for this stroke of the engine. Now let it be understood that from an increase'of the load on the engine the governor cuts off steam at one-third of the next stroke of the initial cylinder and that the exhaust-pressure resultin g therefrom will be thirty-eight pounds, or three pounds more than the pressure in the receiver. This would cause a loss of three pounds in the pressure of the steam discharging into the receiver without doing any work. By my invent-ion, however, the proportionate cut-off in the two engines can be so regulated that there will be no drop in the pressure of the steam from the initial engine to the receiver, because the initial engine cuts off later in the stroke, as above described. The action of the governor of the initial cylinder will be immediatelycommunicated to that of the expansion-cylinder, and by its action on the link U and through it, as above described, with the cut-off mechanism, the expansion-cylinder will cut off earlier, and by thus taking less steam from the receiver than is discharged into it from the initial cylinder the pressure in the receiver will be kept high enough, so that when the exhaust takes place from the initial cylinder it will find a pressure in the receiver equal to its own, thus preventing-the drop in the pressure above described.

The exact proportions of the respective cut-offs for each cylinder depend properly upon the proportions of the cylinders and receiver in each individual case, and also to some extent on the pressure of the steam employed. The invention may be applied to any automatic cut-off gear, and is equally applicable to triple and quadruple expansionengines.

In orderto regulate the momentum of the governor, I employ a circular cast-iron case I), having a vertical partition made through its center. This case contains mercury upon each side of the partition to about two-thirds of its depth, the axis of the case lying horizontally, as shown. The lower part of the case has a regulating-pipe d, provided with a valve or cook, this pipe connecting the two spaces separated by the partition. The valve is set to regulate the flowof mercury from one part to the other. A lever-arm 6 upon a shaft upon which this case is journaled is connected with the lever I by a rod f, so that when the governor acquires a considerable momentum, either from an increase or decrease in the speed of the engine, it will act to turn the case on its axis, and by so doing the mercury in the case will compress the air in the upper part on one side and rarefy it on the other side, while the mercury can flow through the pipe, thus acting as an elastic dash-pot to resist the momentum of the governor and prevent its moving too far in the acquired direction. The connecting-lever is slotted, so that the connecting-rod pin g may be moved nearer to or farther from the cen; ter to give more or less angular motion to the case with mercury, as may be required.

Having thus described myinvention, what I claim as new, and desire to secure by Letters Patent, is

1. The initial and expansion cylinders,with their respective cut-off mechanisms and the governors by which said mechanisms are actuated, in combination with a connecting mechanism whereby said governors operate simultaneously and an oscillating link, together with a block adjustable in said link and connected with the cut-off mechanism of the expansion-engine, substantially as and for the purpose herein described.

2. The oscillating link connected with a lever which is moved by the action of the governors of the initial and of the expansion engines, a block fitted to said link and adjustable to eitherside of its center of oscillation, with a radius-rod connecting said block with the arm of the rocker-shaft, through which the cut-off mechanism of the engine is controlled, substantially as described.

3. The engines having the cutoff mechanism and the governors by which said mechanisms are controlled, in combination with the mercury-air dash pots by which the momentum of the governor is checked, substantially as described.

4. The dash-pot for checking the momentum of the governor, consisting of a circular hollow case mounted upon a horizontal shaft, a crank-arm connecting said shaft with a governor, a vertical partition separating the illterior of said case, and a body of mercury partially filling said space and acting upon the confined bodies of air, substantially as de scribed.

5. The mercury-air dash-pot for checking the momentum of the governors, consisting of a hollow case divided into two compartments by a vertical partition, the said compartments being partially filled with mercury, a connecting-pipe uniting the lower part of the compartments and having an adjusting cock or valve, said case being journaled upon a horizontal shaft and having an adjustable crank-arm, by which it is connected with the moving parts of the governor, so as to be oscillated from side to side, substantially as described.

6. The cut-off mechanisms of theinitial and expansion cylinders of a compound engine, in combination with an intermediate mechanism whereby the cut-off of the expansioncylind'er is caused to take place either simultaneously with, later, or earlier than that of the initial cylinder, substantially as described.

In witness whereof I have hereunto set my hand.

JOHN on. HENRY s'rrrr.

Witnesses:

S. H. NoURsE, H. 0. LEE. 

